County



UNTED STATES PATENT OFFICE.- .v

sAML. e. LEvis, or DELAWARE COUNTY, rENNsrLvANns.

MAKING THicx PAPER.

Specification forming part of Letters Patent No. 10,519, dated Februaryl 14, 1.854; Reissued October 22, 1867, No. 2,789. l

To all whom t may concern Be it known that I, SAMUEL Grd. LEVIS, of the county of Delaware and State of Pennsylvania, have invented a new and useful Improvement in the Construction of Machinery for Making Paper; and I do hereby declare that the following is a full', clear, and exact description of the construction and operation of the same, reference being had to the annexed drawing, which represents a perspective view of my improvement.

In the ordinary manufacture of paper the paper is made in a continuous sheet of a single uniform thickness in the following manner. A cylinder of fine wire cloth rotates partially immersed in a vat of prepared pulp-this cylinder rotates in contact above with an endless felt passing around a roller; and on to the felt the paper is formed by the rotating cylinder of wire cloth pressing the lpulp .which it has taken up from the vat.

The paper thus formed is carried upon the endless felt between two metallic squeeze rollers and the water partially squeezed out. The paper then leaves the felt and is passed between a second pair of squeeze rollers and then around a series of calenders or drying rollers. This is the ordinary method of making paper by cylinder machines; and the paper so made is of one thickness and uniform texture throughout. The thickness which can be given to paper so made, consistently with the preservation of strength and uniformity of appearance, is limited: for the meshes of the wire cloth cylinder can only screen a given quantity of water through and if the thickness of the layer of pulp be increased beyond a certain extent, the paper would .be soft and be crushed between the squeeze-rollers. Thus its texture would be weakened, and the uniformity of its appearance would be destroyed.

It has been long desirable in the art of paper making to form paper of considerable thickness, of perfect texture and of strength proportioned to such increased thickness.

To attain this object, several attempts have been made. Thus, the paper after being formed on the felt and passed through the two pairs of squeeze rollers has been wound upon a reel before passing over the heated calenders. The undried paper so reeled has been passed a second time between the'form-v ing cylinder and the felt and a second thickness of pulp or paper formed upon the first sheet.` It was then passed again through the i two successive pairs of squeeze rollers as before and over'the drying rolls or calenders.

The first sheet in this case being compacted and squeezed partially dry before the second sheet of pulp was formed on to it, the two by the first of the cylinders, a second sheet of pulp or paper wasfformed upon the first sheet by the second forming cylinder. This process required a single felt, .the ordinary squeeze rollers and an additional 'forming cylinder turning in the same vat and in the same direction as the former cylinder.V It

answered very well for thin paper; but when the thickness of the paper was increased, the

second forming cylinder would crush the Y rst formed sheet and thus destroy its uniformity of strength and texture in the same way as describedabove upon vthe ordinary .cylinder lprocess'.

The nature of my improvement consists in an arrangement and combination of machinery for simultaneously forming two distinct fabrics of paper, and uniting them into one compound sheet by continuous 'opera-`V tion and so that these component fabrics shall be inseparably united; by this improvement also, the thickness ofV t-he paper may beV increased and the strength and uniformityV of the sheet of paper be preserved.

To enable others skilledV in the art 'to make and use my improvement, I proceed to describe the construction arrangement and operation of my improvement. t

In my improved arrangement I employ two separate pulp vats A and B (see ligure) In each vat a forming cylinder of wire cloth of the ordinary description is placed. These are shown at C and D. Each cylinder is lfurnished with a separate and distinctendless felt or blanket. The cylinder C forms its pulp or paper on to the felt E shown in red line on the drawing. `The sheet of pulp passes on the lower side yof the felt E in the direction of the arrow a, toward the pair of squeeze rollers F F. The second forming cylinder D rotates in the pulp vat B, in the direction indicated by the arrow thereon, and forms a 'sheet of pulp Von to the endless felt or blanket H shown inblue line. This pulp or paper thus formed upon the felt H passes upon that felt toward the squeeze rollers F, F as indicated vby the arrows h, L. The two endless felts with their respective sheets of pulp pass together over the guide roller K and under the guide roller K; and then between the squeeze rollers F F-the two sheets of paper being in contact while the felts pass between the squeeze rollers are effectually united together and a portion of the water is squeezed out. The squeeze rollers F F perform no other function than to press these two sheets together and the force by which they are v kept together is to` be adjusted thereto. The compound sheet of paper resulting from the union of the two separate sheets as above'passes down along with the felt H as indicated by the arrow L, and through the squeeze rollers L L which perform to it the'rsame function as the first pair of squeeze rollers in ordinary paper machines. The paper then passes through a second pair of squeeze rollers and on to the heated calenders in the same manner as in ordinary machines. It will thus be seen, that I make use of a' second forming cylinder, a second endless felt and an additional pair of squeeze rollers.

The advantage of this improved arrangement is such that paper of any desired thickness, and of proportionately increased strength composed of two layers may be formed at one operation. This arrange- -less cost than the other methods hereinbefore described. Moreover, as the cylinders C & D rotate in separate and distinct vats, paper may be Vformed in the same manner which shall be of dierent colors or different textures on the two sides-or of both different colors and textures on these sides. This will be found of advantage in the manufacture of bonnet boards, plateV paper, fancy paper, &c.

Having thus described my improvement in paper machinery I do not desire to claim generally the employment of two forming cylinders for the purpose of making paper of increased thickness as cylinders have been thus used before; but what I claim as new in my Vinvention and desire to secure by Letters Patent is.-

The combination of the two forming cylinders C & D, the two endless felts E and I-I, and the two squeezerollers F F arranged and operating in the manner and for the purpose substantially as hereinbefore described.

SAMUEL G. LEVIS. Witnesses GEORGE i I-IARDING, CHARLES D. FREEMAN.

` [FIRST PRINTED 1913.] 

